1. Field of Invention
The invention relates to an inverter system and a detecting device thereof, and, in particular, to an inverter system and a detecting device thereof capable of detecting spark phenomena.
2. Related Art
A cold cathode fluorescent lamp (CCFL) has been widely used in various electronic products to serve as a light source or a backlight source. An inverter system boosts a low voltage to a high voltage equal to several hundreds to several thousands of volts for the CCFL.
Because the inverter system is a high voltage circuit, high voltage sparks tend to occur, thereby causing the user to be dangerously shocked or the elements to burn out. Thus, the conventional inverter system has an open-circuit protection circuit and a short-circuit protection circuit for the CCFL to ensure that the inverter system can shut the output of the high voltage down when the CCFL fails and thus prevent the whole circuit from being damaged accordingly. The conventional inverter system only can detect whether the CCFL fails but cannot detect the abnormal condition when the CCFL works normally but the other elements or circuits become abnormal (e.g., when the high-voltage spark occurs) and thus fails to shut the output of the high voltage down in such abnormal conditions. Thus, the user still may be shocked or the elements may burn out.
In view of the above-mentioned problems, a spark protection circuit has been disclosed in, for example, U.S. Patent Publication No. 2004/0012381, in which a wire abuts against a high-voltage loop of an inverter system. Sensing a magnetic flux change in the high-voltage loop can induce a voltage change of the inverter system and thus detect when a spark phenomenon occurs. However, the above-mentioned method needs to additionally add wires and cores, and the overall interconnection complexity and the number of elements are increased. In addition, the dimension of the wire and the distance between the wire and the high-voltage loop cannot be easily controlled. As a result, the magnetic flux change may be not precise enough, thereby influencing the detection result.
Thus, it is an important subject of the invention to provide an inverter system and a detecting device thereof capable of precisely detecting spark phenomena.